USCA Sidecar Forum

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We're in!

We bought a sidecar rig from seller listing on the forum. An '05 R1200RT with a HanniganLT.
Really excited to get it and find some empty space to practice.
We have about three dozen bikes that we collected over the years but our first sidecar. Having a couple of issue with the ABS servo on the bike which need to be sorted out and a general going over, but looking forward to the riding experience.
Anyone with experience on the early BMW servo assisted brakes? would like to hear from you.

Congrats on the purchase. Can't help you with the brakes, but a quick Google search turned up this--

iABS (also known as ABS III or servo-assisted integrated ABS) is BMW’s third generation of motorcycle ABS. This module uses servos to boost the brake pressure in addition to ABS functionality. Common faults include failed servo motors, damaged pumps, failed pressure sensors, leaking pumps and loss of communication.

THAT really narrows it down! LOL

If you're looking for parts on eBay. I found this list of bikes that use the same ABSIII system--

  • R1200GS (K25) – 2003, 2004, 2005, 2006 (part #: 34517698296)
  • R1200GS Adventure (K25) – 2005, 2006 (part #: 34517698296)
  • R1200RT (K26) – 2005, 2006 (part #: 34517698296)
  • R1200RTP (K26) – 2005, 2006 (part #: 34517698296)
  • R1200ST (K28) – 2005, 2006 (part #: 34517698296)
  • K1200S (K40) – 2004, 2005, 2006 (part #: 34517698296)
  • K1200R (K43) – 2005, 2006 (part #: 34517698296)
  • K1200GT (K44) – 2006 (part #: 34517698296)

There's also a DIY article at the Hogranch on bleeding the ABSIII system, but this is apparently the bleed from hell. Might be better off getting the dealer to bleed it. Here's the link--

Congratulations on the rig! The Hannigan is a really nice touring sidecar and the RT should pull it right smartly.

Your ABS issue could be as simple as being low on fluid or a low battery. On my 2004GT with iABS (boosted, or "whizzy" brakes) the reservoir is a split unit (front/rear) located on the right side, just behind the rider's thigh, and the rear half is tough to get to. Topping it up has cleared the ABS fault every time on my bike. As a check, you could have a dealer read the fault code (about $70 at most dealers) or ask around in the local BMW community for someone with a GS911 tool, which does a great job of reading the codes and making numerous adjustments.

iABS is quite sensitive to battery voltage so make sure yours is up to snuff. It helps a bit to wait 10 seconds or so after turning on the key before firing up the bike, so all the self-checks can complete happily before the battery is called upon to spin the motor. And if the ABS doesn't reset and clear the fault light when the bike starts moving, ride a few blocks then stop and restart the bike--that usually clears the warning.

Brake bleeding is kind of a pain on these, but doable if you are patient and invest in a couple of special tools that are needed. One is a long-necked funnel that screws onto the reservoir ( and the other a small wrench that has been heated and bent. Or, one can buy the factory tool$$... I'd suggest you visit and poke around for the iABS brake bleeding documentation, which also describes the tools needed. I personally find better info there than on ADVrider, and in a And, you always have the option of having a dealer do the flush and bleed, typically around $200-250. Fluid was originally supposed to be changed frequently on these bikes, but subsequent service bulletins call for a more extended schedule requiring flushing only every 2-3 years in normal conditions. Being in a dry climate helps extend those intervals to their maximum.

Enjoy the ride and welcome to the forum!



Thanks for the wealth of info!
Have done the battery check.
Have changed fluid and bled the fronts. They work fine.
Although the system is German overly complicated, the bleeding is pretty straight forward once you buy an overpriced funnel adaptor.
It appears that it is the rear circuit which isn't getting any love from the servo module.
Had a side issue that the rear bleeder screw was rusted to the bleeder so naturally broke off so had to remove banjo which means starting from scratch on filling/bleeding. New double banjo w/bleeder on the way. Hoping upon hope that the root cause of the problem was just low fluid or air in the line.
At least when I get the rear filled an bled I can get it to a dealer for a scan. Will be my first trip ever to a dealer for service. Sad.

Will keep you posted.

First trip to a dealer for service? And a BMW dealer to boot? Hold onto your wallet. In my area, the labor rate runs about $120/hour.


Just thinking--steel brake lines? Because if you have the OEM rubber lines, they are known to dissolve from the inside out sending debris into the system.

Sounds like you don't need any other advice. Good luck getting it sorted out and be sure to post some photos with a smile on your face once you get it running right!

Labor rates that high are sure to convince more people to become home mechanics.

$120 is a bit higher than what I'm used to seeing, but $85-100/hr is not at all uncommon for marque shops in the Salt Lake area, and is also pretty much in line with what is being charged at local car dealerships. The good news is, today's equipment tends to require less service than machines of yore. The bad new is, many of the formerly simple tasks--like fluid/filter changes, tire changes, or basic tune-ups--are now more complicated due to bodywork, sensors, electronic complexity, etc. etc. For me, a greater concern is that it seems to be increasingly difficult to find service personnel and mechanics whom I feel I can fully trust to work on my equipment. Bringing a machine home from dealer service only to find body panel screws not tightened or fluids levels not correctly set leaves me questioning ALL the work that was done. Back when I worked in a MC shop we had a standing rule that no serviced machine was turned loose until it had been test ridden by an employee. Today, it's not uncommon to see machines rolled on/off the lift without any test ride at all. For those and other reason$ I still do as much of my own service work as possible and spend both time and money acquiring the necessary knowledge and equipment to do so. At least, up to the point where the equipment--like diagnostic tools--becomes too expensive to justify.



I ride a 1995 K1100 with a Motorvation Formula. My ABS got to be such a pain that I pulled the relay and the light in the instrument cluster to disable the ABS. The bike was ABS and the sidecar wasn't. The brake on the sidecar has a separate pedal that is mounted next to the bike brake. When pressing on the bike brake your foot also presses on the sidecar brake. Your system may be totaly different but that solve my problem. I am not recommending that solution for you but it solved my problem. I have probably ridden 30,000 miles this way.

I take my BMW R1100 w/EZS to a local certified BMW independent. His hourly rates are very reasonable compared to the local BMW dealer. When I first bought the rig 6 years ago, the dealer charged one rate for solo bikes and about $30 an hour more for sidecar rigs. Certainly made no sense to me to charge more for sidecars but when I suggested they should charge straight time and if they have to remove the car simply charge for the time it takes to remove/replace. They wouldn't budge. If you're in Portland, I highly recommend Cheshire Motorsports. Dario is very capable and honest.